1. Field of the Invention
The present invention relates generally to a broadcast receiving system capable of concurrently supporting time-delayed viewing and recording/reproduction of a broadcast signal, and in particular, to a video stream processing method in which a circular buffer, assigned on a recording medium surface for time-delayed viewing, is constituted of discontinuous blocks.
2. Description of the Related Art
Due to its advantages of random access, high data transmission rate, low price, and large capacity as compared to other auxiliary storage devices, a hard disk drive (HDD), which is an auxiliary storage device of a computer system, is used as a random access storage device for a broadcast receiving system.
Such a broadcast receiving system enables simultaneous recording/reproduction with time-delayed viewing of broadcast video streams by controlling buffering of the video streams input/output to/from the HDD.
A description will hereinbelow be given of a method of arranging video streams on a hard disk recording area that is a recording medium in the broadcast receiving system.
FIG. 1 illustrates a method of managing a hard disk as a circular buffer in a broadcast receiving system for time-delayed viewing. FIG. 2 illustrates a method of arranging a plurality of video streams discontinuously in the hard disk recording area.
Referring to FIG. 1, video streams are recorded in blocks of a fixed size when part of the hard disk recording area is managed in the form of a circular buffer. After a write point W and a read point R are designated, new video streams are recorded clockwise or counterclockwise from the write point W and a particular video stream is read by random access at an arbitrary time point in the circular buffer.
When video streams are discontinuously arranged as shown in FIG. 2, the hard disk recording area is divided into blocks of a fixed size and recorded video streams are stored in logical video file units, each logical video file occupying a plurality of blocks. In this case, the blocks of each video file are not always consecutive physically because discontinuous free blocks arise from deletion of video files of different sizes. Information associated with each video file (e.g., title and time) and information about the positions of blocks in the video file are recorded in a separate control information area 36. A video stream storing area 38 has video stream blocks arranged discontinuously. Pluralities of the video stream blocks form video files #1, #2.
The management of the hard disk area in the form of a circular buffer as shown in FIG. 1 incurs access time delay of a head since video streams are successively arranged. Consequently, two separate areas for time-delayed viewing of one channel and recording/reproduction of another channel should be alternately accessed when time-delayed viewing is implemented simultaneously with recording/reproduction.
A broadcast receiving system, if it employs the discontinuous video file arranging scheme shown in FIG. 2, can use the hard disk recording area flexibly and record video streams in files. However, the broadcast receiving system cannot implement continuous recording in a limited area as given in the circular buffer since free blocks are scattered. As a result, a time delay occurs in head movement.